|SOUSA, A - The University Of Porto|
|SOUZA, H - The University Of Porto|
|LIU, S - Chung Shan Medical University|
|GONCALVES, M - The University Of Porto|
Submitted to: International Journal of Biological Macromolecules
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/17/2015
Publication Date: 6/23/2015
Citation: Sousa, A.M., Souza, H.K., Uknalis, J., Liu, S.C., Goncalves, M.P., Liu, L.S. 2015. Improving agar electrospinnability with choline-based deep eutectic solvents. International Journal of Biological Macromolecules. 80:139-148. DOI: 10.1016/j.ijbiomac.2015.06.034.
Interpretive Summary: Agar, a polymer extracted from red seaweed, is a biocompatible and biodegradable substance. Agar fibers have been used to prepare wound dressings and as gelling agents. However, agar fibers are made by a method that uses harsh chemicals. In the present research, pure agar fibers with submicron sizes, which can only be seen using a microscope, were obtained by electrospinning aqueous agar solution containing environmentally benign salts. Electrospinning applies a high voltage to the solution which causes the water to evaporate leaving behind the fibers. It was also found that inclusion of a small amount of the polymer, polyvinyl alcohol, improved the quality of the agar fibers. The results from this study indicate new opportunities for utilization this technology to manufacture improved agar-based biomaterials.
Technical Abstract: One percent agar (% wt) was dissolved in the deep eutectic solvent (DES), (2-hydroxyethyl) trimethylammonium chloride/urea at a 1:2 molar ratio, and successfully electrospun into nanofibers. An existing electrospinning set-up, operated at 50 deg C, was adapted for use with an ethanol bath to collect the fibers. Agar-in-DES showed improved viscoelasticity and hence, spinnability, when compared to agar-in-water, if working above the temperature of the sol-gel transition. The addition of polyvinyl alcohol (PVA; 5% wt) further improved agar-in-DES spinnability; i.e., the viscosity increased and the gelation temperature decreased. The electrospun composite fibers were mostly in the submicron range in size. Processing agar fibers at the submicron scale could be quite useful since the fibers afford performance and properties not seen in the bulk materials. DESs can be sustainable tools to this end.